The present invention relates to a cartridge, and an image forming apparatus in which the cartridge is detachably mountable.
An image forming apparatus is an apparatus which forms images on a piece of a recording medium with the use of an electrophotographic image formation process. Examples of an image forming apparatus are electrophotographic copying machines, electrophotographic printers (for example, LED printers, laser beam printers, and the like), electrophotographic facsimiles, and the like.
A cartridge is a such a cartridge that integrally comprises an image bearing member, and at least one component among a charging means, a cleaning means, and a developing means, and is rendered detachably mountable to the main assembly of an image forming apparatus.
The application of the present invention is not limited to a cartridge which comprises an image bearing member. In other words, the present invention is also applicable to a development cartridge which does not have an image bearing member, and instead has a developing device integral with a hopper in which toner is accumulated, and which is detachably mountable to the main assembly of an image forming apparatus, and is applicable to image forming apparatuses in which such a development cartridge is detachably mountable
A conventional image forming apparatus which employs an electrophotographic image formation process employs a process cartridge system, according to which an electrophotographic photosensitive member, that is, an image bearing member, and one or a plurality of processing means which act on the electrophotographic image bearing member are integrated in the form of a cartridge detachably mountable to the main assembly of an image forming apparatus. With the employment of this process cartridge system, an image forming apparatus can be maintained by a user him/herself without relying on service personnel, remarkably improving operational efficiency. Thus, a process cartridge system has come to be widely used in the field of an image forming apparatus.
A process cartridge such as the one described above is provided with a photosensitive drum, which is an image bearing member, and a developing means for adhering developer (toner) to a latent image formed on the photosensitive drum. A developing means has a developing-means housing and a toner housing, which are connected to each other. The developing means housing holds a development roller which is a developer bearing member, and the like members. The toner housing is a developer holding portion which holds toner. Prior to the first time usage of a process cartridge, a developer outlet, which is an opening located in the joint between the toner housing and developing means housing, is sealed with a sealing member. Therefore, as a brand-new process cartridge is installed into the main assembly of an image forming apparatus to be used for the first time, the sealing member, which is sealing the opening of the toner housing, must be broken or removed. Thus, some process cartridges are equipped with an automatic sealing member removing apparatus, and some image forming apparatuses are known to be enabled to drive such an automatic sealing member removing apparatus of a process cartridge.
An automatic sealing member removing apparatus has the following problems. The occasion at which a user installs or removes a process cartridge into or from the main assembly of an image forming apparatus is not limited to when the currently used process cartridge must be replaced with a fresh one due to the expiration of its service life. For example, the same operation is carried out when a paper jam in the main assembly of an image forming apparatus must be taken care of. In recent years, the size of the main assembly of a laser beam image forming apparatus has been substantially reduced, and therefore, it is common practice to remove the process cartridge from the main assembly of the image forming apparatus before taking care of a paper jam in the main assembly of the image forming apparatus. The motor of the aforementioned automatic sealing member removing apparatus may be rotated to wind away a sealing member each time a process cartridge is installed into the main assembly of an image forming apparatus because there is the possibility that the cartridge being installed is a brand-new one. However, it is wasteful to carry out this sealing member opening operation when the sealing member of the process cartridge has been already wound away; for example, immediately after a paper jam has been taken care of, that is, when the user knows that the sealing member has been pulled away, and therefore is expecting that printing will start immediately. Thus, a user sometimes feels irritated with this wasteful down time during which the motor is turned on and rotates idly, that is, without winding away the sealing member, after a paper jam has been taken care of.
The primary object of the present invention is to provide a cartridge and an image forming apparatus which are capable of automatically sensing whether or not the sealing member for sealing the toner supply opening of the cartridge has been opened
Another object of the present invention is to provide a cartridge and an image forming apparatus which do not repeat a sealing member opening operation when the sealing member has been opened.
Another object of the present invention is to provide a cartridge and an image forming apparatus, the power source of which for opening the sealing member is enabled to determine the actual amount of force necessary to open the sealing member.
Another object of the present invention is to provide a cartridge and an image forming apparatus which are provided with a mechanical power source substantially dedicated or substantially exclusive for providing the force for opening the sealing member.
These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings.